There is no *.bs file supplied with the extension. Instead a
*_BS file which has code for the special cases, like posix for
berkeley db on the NeXT.
This file will get parsed, and produce a maybe empty
@DynaLoader::dl_resolve_using array for the current architecture.
That will be extended by $BSLOADLIBS, which was computed by Andy's
extliblist script. If this array still is empty, we do nothing, else
we write a .bs file with an @DynaLoader::dl_resolve_using array, but
without any ifs, because there is no longer a need to deal with
special cases.
The *_BS file can put some code into the generated *.bs file by placing
it in $bscode. This is a handy 'escape' mechanism that may prove
useful in complex situations.
If @DynaLoader::dl_resolve_using contains -L* or -l* entries then
Mkbootstrap will automatically add a dl_findfile() call to the
generated *.bs file.